Load brake apparatus.



UNITED STATETSJ ATENT OFFICE;

CLYDE C. FARMER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTING- HOUSEAIR BRAKE COMPANY, OF PITTSBURG, PENNSYLVANIA, A COR- PORATION OFPENNSYLVANIA.

LOAD BRAKE APPARATUS- Specification of Letters Patent.

Patented May 28, 1907.

To all whom it may concern:

Be it known that I, CLYDE O. FARMER, a

citizen of the United States, residing in Ohiwhich the following is aspecification.

This invention relates to fluid pressure brakes, and more particularlyto apparatus of this character which may be adapted to give lightbraking power upon a car when empty and heavy braking power upon the carwhen loaded.

It is a well known fact that in order tosecure the most efiicientbraking the power with which the brakes are applied should be inproportion to the weight of the load on the car, that is, a much greaterbraking pressure may be applied to the brake shoes when the car isheavily loaded than when the car isempty, and without danger of slidingthe wheels. Various devices have been proposed for this purpose, thatmost commonly used being to carry a high pressure in the brake systemsufiicient to produce the proper braking pressure for the loaded carsand then apply safety or blow down valves to the brake cylinders whichmay be out in on the empty cars to limit the brake cylinder pressurethereon to such a degree as may be safely applied without causing asliding of the wheels. Such an arrangement obviously wastes a largeamount of compressed air when the apparatus is set for light brakingpower. It has also been proposed to use an additional auxiliaryreservoir or an additional brake cylinder which may be out in for givingheavy braking power on the car when loaded, but such arrangements havein-' volved complications in the action of the triple valve device,since the sizes of the parts and ports in these valves must be designedto operate with certain relative capacities of auxiliary reservoir andbrake cylinder, consequently when the relative proportions of thesevolumes are varied the action of the triple valve becomes irregular andobjectionable.

The main object of this invention is to provide an improved device forreducing the braking pressure produced upon the car when adjusted tolight braking position, and at the same time avoid all the objectionablefeatures of the prior art devices above mentioned. I

Broadly stated, my invention comprises a reducing valve device adaptedto be cut in between the train pipe and the chamber or space on thetrain line side of the triple valve piston for reducing or limiting thepressure admitted from the train pipe to said chamberand for maintaininga substantially constant difference in the degree of pressure carried inthe train pipe and that in the auxiliary reservoir of the car brakeapparatus. This difference in pressures may be made any amount desiredand is adapted to be maintained both during the time of raising thetrain pipe ressure and also when reducing the same or the purpose ofapplying the brakes whereby the action of the triple valves will beuniform on both the light cars and the loaded cars, but the pressureadmitted to the brake cylinders on the light cars will be less than thatwhich obtains upon the heavy or loaded cars in proportion to lowerdegree of pressure carried in the auxiliary reservoir when the apparatusis set for light braking with the reducing valve device cut in.

I will now describe one form of device embodying my invention, referencebeing had to the accompanying drawing, which shows the device invertical section attached to a standard quick action triple valve.

The triple valve device, with the exception of the cap, may be of theordinary standard construction, which is well understood by all familiarwith this art and needs no further description. According to theconstruction shown, the cap portion 1 of the triple Valve is notprovided with a direct communicating passage from the train pipe passage2 to the piston chamber 3, but has a passage 4 leading from the trainpipe space 2 to the out out cock of my improved reducing valve device,and

another passage 5 leading from the cut out cock to the cap chamber andspace 3 on the nected to the cut out cock by the respective ports 11 and12, while the space between the diaphragms is open to the atmosphere.Pin

'valves 13 and 14 are yieldingly mounted in the hollow abutting stems ofthe diaphragms by means of springs 15 and 16, whereby both valves arenormally closed when the opposing pressures on the diaphragms arebalanced. The valve 13 controls port 17 leading from chamber 9 to thecut out cock while the valve 14 controls port 18 leading from chamber 10to the atmosphere, and the cut out cock 23 is provided with ports 19,20, 21 and 22 for adjusting the apparatus to produce light braking uponempty cars or heavy braking upon loaded cars.

Any desired means maybe provided whereby the opposing forces upon themovable abutment may be balanced by different degrees of air pressuresin the diaphragm chambers, and as here shown this is done by making theexposed area of the diaphragm IOgreater than that of diaphragm 9,whereby a higher degree of pressure in chamber 9 and the train line willbe balanced by a lower degree of pressure in the chamber 10 and thetriple piston chamber For present purposes the device is designed togive a difference in these pressures of about 20 to 30 pounds per squareinch, although it will be readily apparent that this may be varied asdesired by changing the relative exposed areas of the differentialdiaphragms.

The operation of my improved device is as follows: The cut out cockbeing adjusted to the position shown in full lines for light braking,air under pressure from the train pipe passes through passages 4, 19 and11 to the diaphragm chamber 9 and opening valve 13 feeds through ports17, 20 and 5 to triple piston chamber 3 and the auxiliary reservoir andalso through ports 22 and 12 to the diaphragm chamber 10. As thepressure in the train pipe and chamber 9 rises to its normal maximumdegree, say seventy pounds per square'inch, the pressure in auxiliaryreservoir, triple piston chamber and diaphragm chamber 10 will rise to acertain degree less than said maximum, say to fifty pounds per squareinch, due to the differential areas of the diaphragms, for the opposingpressures are then balanced and the springs 15 and 16 hold thediaphragms in central position with both valves 13 and 14 tightlyclosed. Should the pressure upon the triple piston and in chamber 10tend to rise above that of the train pipe less the given differential,the pressure upon diaphragm 8 would then open the valve 14 and permitsuch excess pressure to escape to the atmosphere. Also, when the trainpipe pressure and conse quently the pressure in chamber 9 is reduced fora service application of the brakes, the greater pressure upon diaphragm8 immediately opens valve 14 and reduces the pressure in the chamber 3on the train line side of the triple piston at precisely the same rateas the train pipe pressure is being reduced, thereby securing uniformaction of the triple valve with the other triple valves in the train.lVhen an emergency application is made the sudden reduction of pressurein chamber 9 causes the vent valve 14 to be opened wide so as to producequick-action of the triple valve and the openin of the emergency valvefor supplying air lrom the train pipe to the brake cylinder in the usualman ner. hen the brakes are released the increasing pressure actingupon. diaphragm 7 opens the valve 13 sufficiently to allow the pressureupon the triple valve piston in chamber 3 to rise at the same rate asthe train pipe, as before explained. W'hen the device is adjusted forheavy load braking the cock 23 is turned to the position indicated indotted lines, in which the train pipe is in free open communication withthe triple valve piston chamber through ports 4, 21, 19 and 5, so thatthe auxiliary reservoir is charged to the maximum degree of pressure andthe :1]')[):t1zttlls operates in the usual way. In this position of thecock my improved reducing valve device is entirely cut out and as thepressure therein immediately escapes to tl i atmosphere the diaphragmsare subject to no strains. hen the device is set for light braking theaction of the triple valve is in all respects similar to that in heavybraking, except that on account of the lower degree of pressure carriedin the triple valve and auxiliary reservoir the brake cylinder pressurewhich is produced at each application ol the brakes is less by a certainamount than that produced on the loaded cars.

Among the advantages derived by the use of my improvement are thefollowing: 1st. All Waste of compressed air by blowing down the brakecylinder pressure upon the light cars is prevented, while at the sametime the high brake cylinder pressure may be obtained upon the loadedears. 2nd. It will permit an increase in brake cylinder pressure inemergency applications above that desirable for service applications.3rd. The brake will apply and release uniformly with other brakes in thetrain. 4th. l t may be applied to the present standard apparatus withscarcely any change or alteration. 5th. The device is entirely cut. outand free from pressure when set in heavy braking posit ion. 6th. Leakageunder the valves cannot cause excessive pressure in the auxiliaryreservoir when the device is set for light braking, for the reason thatany excess from such leakage will be discharged to the atmosphere.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is 1. In a fluid )ressure brake, thecombination with a trip le valve, of means f or reducing the pressureadmitted from the train pipe ssesm to the triple valve piston and theauxiliary reservoir.

2. In a fluid ressure brake, the combination with a trip e valve, of areducing valve device interposed between the train pipe and the triplevalve piston.

3. In a fluid pressure brake, the combination with a triple valve, ofmeans for limiting the maximum pressure of the auxiliary reservoir andtriple valve chamber to a degree less than that of the normal maximumtrain pipe ressure.

4. In a uid ressure brake, the combination with a trip e valve, of areducing valve device interposed between the train pipe and theauxiliary reservoir for restricting the maximum pressure admitted to theauxiliary reservoir s1de of the triple valve piston to a certain amountless than that of the train 1 e. P In a fluid pressure brake, thecombination with a trip e valve, of means for maintaining asubstantially constant differential between the train pipe pressure andthe pres sure acting on the train line side of the triple valve piston.

6. In a fluid ressure brake, the combination with a trip e valve, of areducing valve device interposed between the train pi e and the triplevalve piston chamber and aving means for maintaining a substantiallyconstant diflerential in the pressures of said chamber and the trainpipe.

7. In a fluid ressure brake, the combination with a trip e valve, of areducing valve device interposed between the train ipe and the triplevalve piston chamber and having means for varying the pressure on thetrain line side of the triple valve piston at substantially the samerate as the train pipe pressure is varied.

8. In a fluid pressure brake, the combination with a triple valve, of'areducing valve device interposed between the train pipe and the triplevalve piston chamber and operating under a reduction in train pipepressure to reduce the pressure in the triple valve piston chamber atsubstantially the same rate.

9. In a fluid pressure brake, the combination with a triple valve, of areducing valve device interposed between the train pipe and the triplevalve piston chamber, and means for cutting said reducing valve deviceinto or out of operation. v

10. In a fluid pressure brake, the combination with a triple valve, of areducing valve device interposed between the train pipe and the triplevalve piston chamber, and a cock having ports for opening freecommunication between the train pipe and said piston chamher or forclosing said free communication and connecting the reducing valve deviceinto operation.

1 1. In a fluid pressure brake, the cOmbina tion with a triple valve, ofa reducing valve device interposed between the train pipe and the triplevalve piston chamber and comprising valve mechanism and a movableabutment subject to the opposing pressures of the train pipe and saidchamber for controllin the pressure in said chamber.

12. n a fluid pressure brake, the combination with a triple valve, of avalve device having a movable abutment subject to the opposing pressuresof the train pipe and the chamber on the train line side of the triplevalve piston for controlling the supply of fluid. from the train pipe tosaid chamber.

13. In a fluidpressure brake, the combination with a triple valve, of avalve device having a movable abutment subject to the opposing pressuresof the train pipe and the chamber on the train line side of the triplevalve piston for controlling the su ply of fluid from the train pipe tosaid chamber, and from said chamber to the atmosphere.

14. In a fluid pressure brake, the combination with a triple valve, of amovable abutment having differential areas subject to the opposingpressures of the train pipe and the chamber on the train line side ofthe triple valve piston, and valve mechanism operated by said abutmentfor controlling the supply of fluid from the train pipe to said pistonchamber.

15. In a fluid pressure brake, the combination with a triple valve, of amovable abutment having differential areas subject to the opposingpressures of the train pipe and the chamber on the train line side ofthe triple valve piston, and a valve mechanism operated by said abutmentfor controlling the supply of fluid from the train pipe to said pistonchamber, and from said chamber to the atmosphere.

16. In a fluid pressure brake, the combination with a triple valve, of areducing valve device comprising differential diaphragms subject to theopposing pressures of the train pipe and the chamber on the train lineside of the triple valve piston, and valve mechanism operated by saiddiaphragms for controlling the pressure in said chamber.

In testimony whereof I have hereunto set my hand.

CLYDE C. FARMER.

